The overfeeding methods according to the state of the art follow two development trends.

The first trend implies using the compressors, typically turbo compressors, which compress the air or the fuel mixture. This leads to either the increasing of the medium effective pressure till nearly the maximum value implying increasing of the power developed by the engine and accordingly the increase of the number of revolutions corresponding to the maximum power, therefore of the speed, either to the increase of the medium effective pressure for all numbers of revolutions regime, implying a significant increase of the turning torque.

The overfeeding in the above-mentioned cases depends on the functioning principle and the compressor characteristics.

The use of such a mechanical compressor, regardless the chosen constructive solution, is highly increasing the selling price of the vehicle.

The second trend implies the use of the overfeeding method through the oil sump.

This solution has a rather low cost, a high reliability but because of depending on the oil level in the oil sump, the overpressure value may highly vary resulting in significant variations of the power and turning torque values. Additionally, due to the massive oil lubrication of the engine device, a high capacity air-oil separator, which is in fact a gas- dynamics brake, is needed, with damaging results on the obtained overpressure value. This method may be named the wet method of overfeeding.

The method and the installation for internal combustion engines self-overfeeding according to the present invention do not use dividing the oil sump in more working compartments but use the pressure chambers, each placed under each cylinder, totally independent from de oil sump which, in its turn, becomes a simple oil storing recipient. This new method eliminates the massive oil mixture from the delivered under pressure air and is named dry method of overfeeding.

In one embodiment of the invention a four-stroke engine with four series cylinders and spark ignition has a pressure chamber placed beneath each cylinder, the pressure chambers having a determined working volume and being in direct connection with the combustion chamber.

The method for internal combustion engines self-overfeeding, according to the present invention, consists in a first phase in air suction, the air being already filtered, in the pressure chamber. The air penetrates into the pressure chamber through a self- commanded admission valve.

The second phase consists of air compression until a pressure which maintains itself constant regardless the engine number of revolutions.

In the third phase the air compressed is directly delivered under pressure through a self- commanded discharging valve into the combustion chamber of the corresponding cylinder.

The installation for internal combustion engines self-overfeeding, according to the present invention, consists of some pressure chambers whose number is equal with the number of cylinders, some admission tubes which connect an air filter with each pressure chamber, some discharging tubes which connect the pressure chambers and the engine combustion chambers, the air circulating on this route due to some self-commanded admission and discharging valves placed one of each type on the pressure chamber.

The delivered under pressure air from the pressure chambers if filtered of the contained oil by some filtering beds, placed one for each pressure chamber.

The advantages of the method and the installation for internal combustion engines self- overfeeding, according to the present invention, consists of increasing the engine efficiency due to the overpressure with an almost constant value, regardless the engine number of revolutions, at the air feeding, that is the increasing of the power and the engine number of revolutions corresponding to the maximum power and the increasing of the maximum coupler and the determination of a large number of revolutions range in which this parameter has a relatively constant value.

An embodiment of the present invention will be disclosed in connection with the Figures 1... 5 which represents: Fig. 1-schematic assembly view Fig. 2-installation principle diagram Fig. 3-assembly view of the pressure chamber Fig. 4-longitudinal section of the pressure chamber Fig. 5-cross section of the pressure chamber The method for internal combustion engines self-overfeeding, according to the present invention is based on the working cycles differences between the superior and the inferior part of each piston. The working cycles are the following : The superior part of the piston The inferior part of the piston -admission-compression-discharge -compression-admission -combustion-compression-discharge -discharge-admission For each cylinder the piston executes an overfeeding, independently from other cylinders, due to the fact that for a single admission time executed at the superior part of the piston, two complete working cycles are executed at the inferior part of the piston.

Therefore, while the combustion time is executed at the superior part of the piston, the compressed air is discharged, at the inferior part of the piston, into the tubes connecting the pressure chamber with the combustion chamber of the corresponding cylinder. This air is stored in the tubes at a determined pressure, until the working cycles allow the execution of the admission time at the superior part of the piston. Simultaneously, at the inferior part of the piston, the air is compressed and discharged in the discharging tubes where there is already air under pressure.

When the admission valve is opened, the entire quantity of air under pressure penetrates into the combustion chamber of the cylinder, achieving therefore the overfeeding.

In order to obtain a corresponding overpressure, a compression space with a volume as small as possible is necessary to exist at the inferior part of each cylinder. This compression space is obtained due to a pressure chamber 1 composed of two parts A and B (Fig. 2 and 3) profiled in its interior part according to the space formed by the rotating unit crank pin (of crankshaft)-connecting rod. The pressure chamber 1 is provided with two orifices in which an admission valve 2 and a discharging valve 3 are mounted, both being self-commended. When the piston 4 executes the compression time, that is the lifting stroke from the inferior dead point (PMI) to the superior dead point (PMS) the admission valve 2 opens allowing the air admission on the route: air filter 5, admission tubes 6, pressure chamber 1, to be made.

When the piston 4 executes the combustion time, that is the stroke PMS to PMI, the admission valve 2 closes, the air beneath the piston starts to be compressed forcing the discharging valve 3 to open and thus allowing the air under pressure to penetrate into the discharging tubes 7 where it remains stored at a certain pressure. A filtering bed 8 and a oil separator 9, with the role of filtering and separating the air from the oil is also placed in the tubes 7. The resulting separated oil is sent back through a connecting piece 11 to the oil sump 10.

The pressure chamber 1 is connected to the oil sump 10 through a duct 12 whose role is to maintain a direct means of oil flowing from the lubrication sections to the oil sump.

When the piston 4 executes the discharging time, that is the stroke PMI to PMS, the discharging valve 3 is closed and the admission valve 2 is opened, and a new admission phase is starting again.

When the piston 4 executes the admission time, that is the stroke PMS to PMI and the admission valve from the cylinder head is opened, the air which is already under pressure in the tubes 7 penetrates the combustion chamber, due both to the pressure differences and the fact that the air placed beneath the piston 4 starts to be compressed and discharged in the tubes 7, exerting a new pressure.

Bibliograhhy -The"Autoturism"Revies collection 1985-2000 -Patent RO 108055/1993 -Vsevoldo Radcenco : The computing and projecting of the pneumatic automatization elements and schemes, Editura Tehnica 1985